CN102270688A

CN102270688A - Solar cell

Info

Publication number: CN102270688A
Application number: CN2010101993193A
Authority: CN
Inventors: 刘爱民; 曹英丽; 赵秀芹
Original assignee: JINZHOU HUACHANG PHOTOVOLTANIC TECHNOLOGY Co Ltd
Current assignee: JINZHOU HUACHANG PHOTOVOLTANIC TECHNOLOGY Co Ltd
Priority date: 2010-06-01
Filing date: 2010-06-01
Publication date: 2011-12-07

Abstract

The invention relates to a solar cell. The solar cell comprises a silicon wafer 1, an inversion layer 12 made on the silicon wafer 1 by a diffusion method, a texture surface 13 made on the silicon wafer 1, a silicon nanometer layer 14, a passivation layer 5, an upper electrode grid line 6 and a lower electrode 7, wherein the silicon nanometer layer 14, the passivation layer 5, the upper electrode grid line 6 and the lower electrode 7 are made on the texture surface 13 by an etching method; a part 11 and the inversion layer 12 of the silicon wafer 1, of which the electric conduction types are not changed in thermal diffusion, form a PN junction required by the solar cell; the upper surface of the solar cell is the texture surface 13; and the silicon nanometer layer 14 is etched on the upper surface and can be used for improving the surface roughness. Based on the quantum size effect of a nanometer material, the absorption rate and the utilization rate of the solar cell to visible light and ultraviolet light are greatly improved, so the efficiency of the solar cell is improved.

Description

A kind of solar cell

Technical field

The present invention relates to a kind of new body silicon solar cell, relate in particular to a kind of solar cell that on the silicon wafer suede structure, prepares the silicon nanometer layer.

Background technology

Solar energy is inexhaustible, nexhaustible clean energy resource.Solar cell is the device that solar energy is converted into electric energy.Wherein, the body silicon solar cell that comprises monocrystalline silicon and polysilicon solar cell in this field always in occupation of consequence.

An important step that improves conversion efficiency of solar cell is to reduce the reflection of incident light rate, strengthens absorption of incident light and utilization.Usually the method that reduces reflectivity has: (1) prepares one or more layers antireflection film; (2) utilize chemical etching method to prepare pyramid structure or inverted pyramid structure or other bowl configurations etc., reduce reflectivity as matte; (3) above-mentioned two kinds of methods are combined.Said method or equipment needed thereby costliness, or be exactly that reflectivity is still relatively large, the light absorption utilance still needs to improve.Wherein (2), matte micro-structural of the prior art is mainly pyramid structure, inverted pyramid structure or bowl configurations, the size of its single pyramid, inverted pyramid and pit is generally greater than 1 micron, or about 1 micron, do not have the quantum size effect of nano material.

Given this, the present invention proposes preparation silicon nanometer layer on the surface of above-mentioned (2) described pyramid, inverted pyramid or pit, and the silicon nanometer layer is made of the nano wire or other silicon nano material that have less than 100 nano-scale features.The silicon nanometer layer makes the surface more coarse, utilizes this composite construction reflectivity can be reduced to 1%, even lower, and the silicon nanometer layer can strengthen absorption of incident light and utilance.The silicon nanometer layer is as nano material, and its quantum size effect also improves its absorption and utilance to visible light and ultraviolet light especially.Thereby raising conversion efficiency of solar cell.

Summary of the invention

Accompanying drawing 1 is the body silicon solar battery structure schematic diagram that the present invention relates to, by silicon chip 1, the inversion layer 12 that utilizes the impurity thermal diffusion technology on silicon chip 1, to prepare, at silicon nanometer layer 14, passivation layer 5, the top electrode grid line 6 of the matte 13 of preparation on the silicon chip 1, preparation on matte 13, bottom electrode 7 constitutes.In the impurity thermal diffusion process, do not change the part 11 of its conduction type and the inversion layer 12 of its conduction type of change in the silicon chip 1 and form PN junctions.For example: if silicon chip 1 is the N type, 11 parts keep the N type, utilize diffusion technique at silicon chip 1 surface preparation P type inversion layer 12; If silicon chip 1 is the P type, 11 parts keep the P type, then utilize diffusion technique at silicon chip 1 surface preparation N type inversion layer 12.In PN junction, form the needed built-in electromotive force of solar cell.On the teaching material of semiconductor applications, have a detailed description utilizing diffusion technique to prepare PN junction.The characteristics of this solar cell are to be etched with silicon nanometer layer 14 on silicon wafer suede 13.

The body silicon solar cell of prior art does not have silicon nanometer layer 14, incident light only antireflection layers such as silicon nitride by matte 13 and deposition or silicon dioxide reduces reflectivity, and do not have that the quantum effect of nano material causes especially to visible light and ultraviolet light enhanced absorption effect.

The present invention discloses and utilizes the method for chemical etching or other lithographic method to prepare the silicon nanometer layer on silicon wafer suede.Except matte 13 plays the antireflective effect, and the nanometer layer on it can become more coarse with the surface once more, reduces the reflection of incident light rate; As nano material, its quantum effect can improve its absorption and utilance to visible light and ultraviolet light especially.

The solar cell that the present invention relates to, its substrate can be n type single crystal silicon, p type single crystal silicon, N type polysilicon and P type polysilicon.Above-mentioned substrate can prepare PN junction by the method for diffusion, all can utilize the present invention to improve its efficient based on the solar cell of body silicon.

Description of drawings

Accompanying drawing 1 is for comprising the silicon solar battery structure figure of silicon nanometer layer, it is by silicon chip 1, passivation layer 5, top electrode grid line 6, and bottom electrode 7 constitutes, and wherein silicon chip 1 comprises the part 11 that does not change its conduction type after the impurity thermal diffusion, the inversion layer 12 that forms after the impurity thermal diffusion, matte 13, silicon nanometer layer 14.

Embodiment

Example 1: with the p type single crystal silicon is example: the silicon chip after the cutting can produce mechanical damage layer at silicon chip surface.Remove the affected layer on surface by the high concentration alkali flush away, utilize the alkali of low concentration and the mixed solution etching silicon chip surface of alcohol then, form the matte of pyramid structure at silicon chip surface, under 860 ℃, carry out phosphorous diffusion with phosphorus oxychloride afterwards and prepare PN junction, lithographic method prepares the silicon nanometer layer then, use the dry plasma silicon chip edge again, prevent edge current leakage, remove phosphorosilicate glass with hydrofluoric acid then, enhancement mode plasma activated chemical vapour deposition method silicon nitride film then, form the passivation layer of battery surface, or double antireflection layer, electric field is carried on the back in silk screen printing back electrode and formation then, the silk screen printing positive electrode, and the oven dry sintering forms the solar cell based on P type silicon chip.

Experimental needs can be after silicon chip surface forms the matte of pyramid structure, and phosphorous diffusion prepares before the PN junction, and etching prepares the silicon nanometer layer; Also can be after the plasma etching silicon chip edge to be finished, etching prepares the silicon nanometer layer; Also can after finishing, the removal phosphorosilicate glass etching prepare the silicon nanometer layer; Or and remove phosphorosilicate glass and carry out simultaneously.

Other also adopts production stage similar to the above based on the solar cell that comprises the silicon nanometer layer of N type silicon single crystal flake, P type polysilicon chip, N type polysilicon chip, and just etching solution, diffusion temperature, diffuse source etc. are according to circumstances specifically adjusted.

Claims

1. solar cell, it comprises:

One silicon chip;

One inversion layer, this inversion layer make silicon chip surface form PN junction;

One top electrode, this electrode is arranged at the upper surface of silicon chip;

One back electrode, this back electrode is arranged at silicon chip back;

It is characterized in that described solar cell surface is a matte, and the silicon nanometer layer is arranged on matte.

2. solar cell according to claim 1 is characterized in that, described matte is by the pyramid of size in 0.1 micron～100 micrometer ranges or the surface that structure constituted of inverted pyramid or pit shape.

3. solar cell according to claim 2, it is characterized in that, the surface of described pyramid or inverted pyramid or bowl configurations is made of the silicon nanometer layer, and the silicon nanometer layer covers the whole silicon wafer surface at pyramid or inverted pyramid or pit place.

4. solar cell according to claim 3 is characterized in that, described silicon nanometer layer is by silicon nanowire array or other the silicon nano material superficial layer formed of silicon crystal in 1 nanometer～100 nanometer feature sizes scopes.

5. solar cell according to claim 1 is characterized in that, deposits passivation layer on the described silicon nanometer layer.

6. solar cell according to claim 1 is characterized in that, deposit passivation layer not on the described silicon nanometer layer.

7. solar cell according to claim 1 is characterized in that, deposits antireflection layer on the described silicon nanometer layer.

8. solar cell according to claim 1 is characterized in that, on the described silicon nanometer layer, does not deposit antireflection layer.

9. solar cell according to claim 1 is characterized in that, described silicon nanometer layer is carried out chemical surface treatment to it, makes surface passivation.

10. solar cell according to claim 1 is characterized in that, described silicon nanometer layer is not carried out chemical passivation to it and handled.

11. solar cell according to claim 1 is characterized in that, described silicon chip is p type single crystal silicon sheet or polysilicon chip, utilizes method of diffusion to prepare N type inversion layer, forms PN junction.

12. solar cell according to claim 1 is characterized in that, described silicon chip is n type single crystal silicon sheet or polysilicon chip, utilizes method of diffusion to prepare P type inversion layer, forms PN junction.